Insights into the absorption of carbon dioxide by zinc substrates: isolation and reactivity of di- and tetranuclear zinc complexes

Abstract

The heptadentate Schiff base H(3)L can react with zinc acetate to form the discrete dinuclear complex Zn(2)L(OAc)(H(2)O), 1.H(2)O. The reaction of 1.H(2)O with NMe(4)OH.5H(2)O both in air and under an argon stream has been investigated. On one hand, this reaction in air yields the tetranuclear complex (Zn(2)L)(2)(CO(3))(H(2)O)(6), 2.5H(2)O, by spontaneous absorption of adventitious carbon dioxide. This process can be reverted in an acetic acid medium, whereas the treatment of 2.5H(2)O with methanoic acid yields crystals of [Zn(2)L(HCOO)].0.5MeCN.1.25MeOH.2H(2)O, 3.0.5MeCN.1.25MeOH.2H(2)O. On the other hand, the interaction under an argon atmosphere of 1.H(2)O with NMe(4)OH.5H(2)O in methanol allows the isolation of the dinuclear complex Zn(2)L(OMe)(H(2)O)(4), 4.4H(2)O. Recrystallisations of 1.H(2)O, 2.5H(2)O and 4.4H(2)O, in different solvents, yielded single crystals of 1.MeCN.2.5H(2)O, 2.4MeOH and 4.3MeOH.H(2)O, respectively. The crystal structure of 2.4MeOH can be understood as resulting from an unusual asymmetric tetranuclear self-assembly from two dinuclear units, and shows three different geometries around the four zinc atoms.

Spontaneous fixation of CO2 by {Ni9} constructed from tauric anion: Synthesis and X-ray structure of [Ni9(NH2CH2CH2SO3)6(CH3CO2)6(H2O)6(OH)6(μ6-CO3)2]4−

“…The core of 1 is similar to that of [Co 10 (OH) 6 (mhp) 6 (O 2 CCPh 3 ) 6 (Hmhp) 3 (HCO 3 ) 3 ] as tricapped trigonal prism. But in 1, carbonate ion acts as l 6 -CO 2À 3 bridging coor-dination mode contributing to the construction of core.…”

“…Complex 1 can also be synthesized when the reactive system was treated by another Schiff base ligand (2-(2-thienyl-methyleneimino)ethylsulfonate) via the same route, while the reaction also undergoes rapid fixation of CO 2 under ambient conditions, as in the system of L À . Higher yields and shorter crystallization time, with Schiff base as intermediate ligand, suggest that Ni-Schiff base complex may be active as a precursor for the fixation of atmospheric CO 2 , which is also observed in other system [6]. The reaction was also performed under an inert atmosphere.…”

“…In the process of exploring the fixation of atmospheric CO 2 , a number of carbonate-based compounds have been isolated [4]. Due to versatile coordination modes of carbonate anion, carbonate-bridging compounds exhibit a variety of structural topology [5][6][7][8][9][10]. Winpenny and coworkers [5] reported that hydroxide polynuclear cages of Co or Ni can activate atmospheric CO 2 into carbonate anions during the process of formation of polynuclear cages, while the afforded carbonate anions act as ligand or template to construct the polynuclear cages.…”

Uncommon Coordination Modes of a Potential Heptadentate Aminophenol Donor

“…The synthesis of the aminophenol ligand 3NO2,5Br-H6L 1,1,4 (Scheme 1) requires the prior isolation of the Schiff base precursor 3NO2,5Br-H3L. This latter was obtained by a previously reported method [6], in a typical Schiff condensation from the corresponding 3NO2,5Br-salyciladehyde and triethylenetetramine (Scheme 1), but this Schiff base has not been described before, and it is original from this work. Its characterization by elemental analysis, IR and 1 H-NMR spectroscopy (see experimental) agrees with its isolation with high purity.…”

Polynuclear alkoxy–zinc complexes of bowl-shaped macrocycles and their use in the copolymerisation of cyclohexene oxide and CO2

“…Multidentate macrocycles are attractive as ligands for di-and polynuclear complexes of transition-and f-block metals as they can control both the basic coordination chemistry and the relative spatial positioning of metals within the macrocyclic framework, so providing a pre-organised chemical environment. [1][2][3][4] This ligand design strategy can deliver a diversity of physical and reaction properties in the resulting complexes leading to, for example, clustering and aggregation, [5][6][7][8][9][10][11][12][13][14] catalytic activity, [15][16][17][18][19][20][21][22][23][24][25][26][27][28] molecular magnetism, 29 allosteric constructs, 30,31 and molecular sensing. [32][33][34][35] We have been studying macrocycles in which two donor compartments comprising two dipyrromethane and two Schiff-base nitrogen donors (i.e.…”